| With gradually aggravated environmental problem,it is hoped that more energies can be found to replace traditional fossil energy.Solar energy as the clean and renewable sourcehas aroused extensive attention.Since Gratzel et al.developed dye-sensitized solar cells(DSSCs),the photo-to-electric conversion efficiency(η)of this type of solar cells has achieved 7.1-7.9%.Due to their friendliness and low cost of production,more attention have been done to investigate their relationship between structure and performance,and to design new DSSCs.Phloxine B and Bromophenol blue as the sensitizers of dye-sensitized solar cells were investigated via UV-Vis spectra,FT-IR spectra,and fluorescence spectra and current-voltage characteristics.The frontier molecularorbital,vibration analysis and the first hyperpolarizability were calculated with DFT/6-31G(d).The dipole moment,light harvesting efficiency(LHE)and larger absolute value of driving force of electron injection(ΔGinjet)were also discussed.We experimentally investigated the photoelectric properties of two indoline dyes(CA2 and CA3).The properties of two dyes were studied through ultraviolet visible spectroscopy,energy levels,and molecular descriptors.The observations were in good agreement with calculations carried out through basis sets corrections.Photoelectric properties of normal model(NM)were computed via the electron injection lifetime,excited state lifetime,fluorescence lifetime,energy difference between the TiO2 conduction band(EcBE),and electron difference between donor and recipient(nc).Photoelectric properties of developed normal model(DNM)were calculated by the transient spectrum,molar extinction coefficient,adsorption capacity,and recombination rate.It was found that compared with Bromophenol blue,bigger dipole moment of Phloxine B results in larger open circuit voltage(Voc)according to the correlation between dipole moment and Voc.Therefore,higher LHE and ΔGinjectect for Phloxine B produce larger value of Jsc.The DNM could not only be used to evaluate Jsc,Voc,and η from considerations on the relationship between the macroscopic properties and microscopic parameters,but also provided an effective method for improving the molecular design and performance tuning by decreasing factors unfavorably affecting the energy conversion process. |
